meadowgrass

from WordNet (r) 3.0 (2006)

meadowgrass
    n 1: any of various grasses that thrive in the presence of
         abundant moisture [syn: {meadowgrass}, {meadow grass}]

from The Collaborative International Dictionary of English v.0.48

meadowgrass \meadowgrass\, meadow grass \meadow grass\n.
   Any of various grasses that thrive in the presence of
   abundant moisture, especially those of the genus {Poa},
   common in meadows, and of great value for hay and for
   pasture. See {Grass}.
   [1913 Webster + WordNet 1.5] meadowlark